From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f50.google.com (mail-la0-f50.google.com [209.85.215.50]) by kanga.kvack.org (Postfix) with ESMTP id F29756B0031 for ; Mon, 2 Jun 2014 12:38:04 -0400 (EDT) Received: by mail-la0-f50.google.com with SMTP id b8so2672109lan.23 for ; Mon, 02 Jun 2014 09:38:04 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id cn1si22569217wib.60.2014.06.02.09.38.02 for ; Mon, 02 Jun 2014 09:38:03 -0700 (PDT) Message-ID: <538ca86b.a15cb40a.56e9.78fcSMTPIN_ADDED_BROKEN@mx.google.com> Date: Mon, 02 Jun 2014 12:37:32 -0400 From: Naoya Horiguchi In-Reply-To: <538CA269.6010300@intel.com> References: <20140521193336.5df90456.akpm@linux-foundation.org> <1401686699-9723-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1401686699-9723-2-git-send-email-n-horiguchi@ah.jp.nec.com> <538CA269.6010300@intel.com> Subject: Re: [PATCH 1/3] replace PAGECACHE_TAG_* definition with enumeration Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: dave.hansen@intel.com Cc: akpm@linux-foundation.org, koct9i@gmail.com, fengguang.wu@intel.com, acme@redhat.com, bp@alien8.de, kirill@shutemov.name, hannes@cmpxchg.org, rusty@rustcorp.com.au, davem@davemloft.net, andres@2ndquadrant.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, Jun 02, 2014 at 09:12:25AM -0700, Dave Hansen wrote: > On 06/01/2014 10:24 PM, Naoya Horiguchi wrote: > > -#define PAGECACHE_TAG_DIRTY 0 > > -#define PAGECACHE_TAG_WRITEBACK 1 > > -#define PAGECACHE_TAG_TOWRITE 2 > > +enum { > > + PAGECACHE_TAG_DIRTY, > > + PAGECACHE_TAG_WRITEBACK, > > + PAGECACHE_TAG_TOWRITE, > > + __NR_PAGECACHE_TAGS, > > +}; > > Doesn't this end up exposing kernel-internal values out to a userspace > interface? Wouldn't that lock these values in to the ABI? Yes, that would. I hope these PAGECACHE_TAG_* stuff is very basic things and will never change drastically in the future (only added), so it's unlikely to bother people about ABI breakage things. Thanks, Naoya Horiguchi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org